Usage metrics do not load
Usage Metrics Dashboard never loads, or the widgets βspinβ indefinitely. This can be caused by a large number (hundreds of thousands or millions) of documents in the MongoDB UsageEntrys collection.
To work around the problem, delete documents from the UsageEntrys collection until the Usage Metrics Dashboard becomes acceptable. To delete documents from the Entrys collection, first backup MongoDB, then connect to MongoDB using either the shell or Robo 3T, and execute this query:
db.getCollection('UsageEntrys').find({}).limit(N).forEach(function(doc){db.getCollection('UsageEntrys').remove({_id: doc._id});})
where N is set to some large fraction of the documents.
Check the Usage Metrics Dashboard performance after executing the query, then repeat until the Usage Metrics Dashboard performance is acceptable.